The DO area is located in the extreme northwest of the Spanish region of Castilla y León. It comprises over 4,000 hectares of vineyards at an altitude of 400 to 800 metres above sea level with over 20 communities on heavy clayey soils, as well as quartzite and slate in the mountainous area. The temperate climate is quite mild. The clearly dominant grape variety with about three quarters of the area is Mencía (Negra), which must be present in 70% of the predominant red wines. Other red wine varieties are Garnacha Tintorera, Cabernet Sauvignon, Tempranillo, Syrah, Prieto Picudo and Petit Verdot. The authorised white wine varieties are Godello, Palomino, Doña Blanca and Malvasía. Well known producers are Agribergidum, Castro Ventosa, Cepas del Bierzo, Descendientes de José Palacios(Álvaro Palacios), Dominio de Tares, Estefanía, Guerra, Paixar, Pérez Caramés, Pittacum and Prada a Tope.